Oenothera is a genus of about 145 species of Naturally flowered plants. These are the genus types of the Onagraceae family. Common names include evening primrose , suncups , and sundrops . They are not closely related to the actual rose (genus Primula ).
Video Oenothera
Description
Species vary in size from a small 10 cm high alpine plant, such as O. acaulis from Chile, to strong upland species growing up to 3 meters, such as O. stubbei from Mexico. The leaves form a basalt rosette on the ground and form a spiral up to the flowering stems. The propeller is dentate or deep lobed (pinnatifid). The flowers of many species open at night, hence the name "evening primrose". They can be opened in less than a minute. Most species have yellow flowers, but some have white, purple, pink, or red. Most of the original desert species are white. Oenothera caespitosa , a western species of North America, produces white flowers that become pink as they get older. One of the most distinctive features of interest is the stigma, which has four branches in the form of X.
Maps Oenothera
Ecology
Oenothera flowers are pollinated by insects, such as moths and bees. Like many other Onagraceae members, the pollen grains are loosely held together by viscin threads, so only morphologically specialized insects to collect this pollen can pollinate the flowers effectively. Bees with a typical scopa can not hold it. Also, the flowers open when most of the bee species are inactive, so the bees that visit Oenothera are generally tempes vespertine specialists: bees looking for food at night. The seeds ripen from the end of summer down.
Oenothera is used as a food crop by the larvae of some species of Lepidoptera, including a large white sphinx. The moth of Schinia felicitata and S. florida feeds exclusively on the genus, and the first is limited to O. deltoides <.
In the wild, the primroses of night act as the main occupiers, rapidly appearing in areas that have recently been cleared. They sprout in disturbed soil, and can be found in habitat types such as sand dunes, roadside, train embankment, and garbage dumps. They often relax and end up competing with other species.
Origin
The genus Oenothera may originate in Mexico and Central America, and spread further north in North America and to South America. With the advent of international travel, species are now found in the temperate regions of the world. In Europe alone there are about 70 species introduced Oenothera . During the Pleistocus era the succession of the ice age swept across North America, with an annoying warm period. This happens four times, and the genus undergoes four separate colonizing waves, each hybridizing with survivors from the previous wave. It forms the current subsition Euoenothera . The group is genetically and morphologically diverse and the species largely infertile, so the boundaries of species have been debated among taxonomists.
Genetics
Repeated colonization patterns produce a unique genetic conformation in Euoenothera where chromosomes in meiosis can form circles rather than in pairs. This is the result of some mutual translocation between the chromosomes so that the pair only occurs at the tip. This phenomenon seems to have a non-Mendel genetic consequence; with chromosomal segregation mode and a deadly-lethal gene system, genetic recombination is prevented and the plant displays the hybrid power of heterosis. This resulted in the evolution of many sympatric races in North America to the east of the Rocky Mountains. The cytology analysis of these races and the artificial hybrids among them enhances the understanding of the genetic and geographic evolution of Euoenothera . This subject was a major area of ​​genetic research during the first half of the 20th century.
The emergence of abrupt change in Oenothera lamarckiana led the pioneering geneticist Hugo de Vries to propose the mutation theory (Mutationstheorie) in 1901. This confirms that the speciation was driven by a sudden large. mutations are able to produce new varieties in one step. The understanding that changes observed in plant hybrids are caused by chromosome duplication (polyploidy) rather than gene mutations did not occur until much later.
Taxonomy
The evening rose is initially assigned to the genus Onagra , which gives the Onagraceae family its name. Onagra (meaning "(food of" onager ") was first used in botany in 1587, and in English at Philip Miller 1754 Gardeners Dictionary: Brief . > Oenothera published by Carolus Linnaeus in his book Systema Naturae .The etymology is uncertain, but it is believed to be derived from the Greek word ???? ????? ( onos theras ), meaning "donkey catcher," or "oinos theras", meaning "wine seeker".
Evidence of medical effects
Certain plants Oenothera have edible parts. The roots of O. biennis are reported to be edible to young plants.
There is little evidence for the effectiveness of primrose oil as a cancer treatment according to the American Cancer Society, and "neither GLA nor other GLA-rich supplements (such as evening primrose oil) have been proven conclusively useful in preventing or treating other health conditions." A Cochrane meta-analysis published in April 2013, found the evening primrose oil capsule and borage oil to be ineffective for eczema.
Most studies show that evening primrose oil given orally does not alleviate the symptoms of premenstrual syndrome, as well as oral primrose oil appears to have an effect in shortening the duration of pregnancy or labor.
Cultivation
A number of perennial members of the genus are generally cultivated and used in landscaping in the southwest United States. Popular species include tufted night primrose (Oenothera caespitosa ), primrose mexican evening ( Oenothera berlanderiii ), and Saltillo evening primrose ( Oenothera stubbei ).
Annual night rose flowers are also popular decorative plants in the garden. Many are quite drought resistant.
The first plants to arrive in Europe reached Padua from Virginia in 1614 and described by the English botanist John Goodyer in 1621. Some species are now also naturalized in parts of Europe and Asia, and can be planted as far as 65 ° N in the north. Finland. The UK National Council for the Conservation of Plants and Gardens, based in Wisley, maintains the Oenothera collection as part of the National Collection scheme.
Gallery
References
External links
- Onagraceae - The Evening Primrose Family. Smithsonian National Museum of Natural History.
- Plants For The Future
- zewczyk, Karolina; Lewandowska, Urszula; Owczarek, Katarzyna (2014). "Effects of Polyphenol Extracts from Evening Primrose (Oenothera Paradoxa) Seeds on Caco-2 Cell Proliferation and Expression, Synthesis and Matrix Activity of Metalloproteinases and Their Inhibitors". Journal of Polish Food and Nutrition . 64 (3): 181-191. doi: 10.2478/pjfns-2013-0003.
Source of the article : Wikipedia
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